Methods and System for Evaluating and Maintaining Disinfectant Levels in a Potable Water Supply

ABSTRACT

A method of determining a disinfectant composition of a municipal water supply from a water sample that includes: (a) obtaining a water sample from a water source at a sampling location; (b) adding a chlorine-containing material to the water sample in the presence of an oxidation reduction potential (ORP) measurement device; (c) generating a plurality of ORP measurements during addition of the chlorine-containing material to the water sample; (d) estimating a concentration of one or more of free ammonia, fully combined ammonia, monochloramine, or a mixture of dichloramine and trichloramine in the water sample in which the estimation is derived from the relationship between the added chlorine material and the plurality of ORP measurements; and (e) determining a disinfectant composition of the water source at the water sampling location from the concentration calculation. A method of determining free ammonia composition is also included.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 62/356,718 filed Jun. 30, 2016, which is incorporatedherein by reference in its entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to methods and devices for evaluating thedisinfectant composition of a potable water supply and, in particular,methods of determining the presence of and estimation of the amounts ofone or more of free ammonia, mono-, di- or tri-chloramines therein aswell as systems for measuring and maintaining the chloramination andfree ammonia levels of a potable water supply.

Description of Related Art

Water used for human or animal consumption must be treated to removepathogens and contaminants. After treatment, a “residual disinfectant”is usually applied to the water to prevent the regrowth of pathogens.This is also termed “secondary disinfection.” In municipal watersystems, chlorine or chloramines (monochloramine: NH₂Cl) are typicallyused for this purpose. Many municipal water systems in the United Statesand abroad increasingly use chloramines, which are chemically morestable and less reactive, and, thus, can persist longer in thedistribution system.

With the increased use of chloramines as a strategy to reducedisinfection byproduct levels in the municipal water supplies, inparticular those used to deliver potable water to consumers, enhancedanalysis and treatment techniques are needed. Municipal water systemsare mandated by mission, as well as regulatory regimes, to ensure thatwater remains safe for human consumption, not only at the treatmentplant location, but at all locations in the delivery system, includingat or near the faucet where the water is finally delivered to theconsumer. Competing with the demand for safety is the need to reduceoff-tasting materials in the water, which, while not necessarily unsafe,can result in consumer perception that the water is unsanitary. As anadditional issue, managers of water supplies must endeavor to treatwater using the most cost-effective methods available, which means thataccurate measurement of required chemical levels and process controlsfor delivering those chemicals are required to ensure that money is notwasted.

Chloramine chemistry has been described for some time, especially inregard to wastewater treatment and the disinfection of water coolingtowers used in air conditioning systems. In these applications, the goalgenerally is to reduce the amount of biological contaminants present inorder to also reduce the possibility of humans or other biologicalsystems from becoming ill from such contamination.

Maintaining proper chloramine chemistry throughout a water distributionnetwork is difficult. At least some free ammonia is typically maintainedin water systems—generally less than about 0.1 mg/L—to better ensurethat chloramination remains effective throughout a water distributionnetwork. Because the chlorine in the molecule reacts with organic matterin the water, some amount of chlorine will be deactivated from use as adisinfectant. As a result, with time, the water can accumulate excessfree ammonia. For other water sources that may be used as potable water,such as wells, free ammonia may be natively present in the water due tobiological and water source artifacts. The presence of free ammoniagreatly increases the risk of nitrification—a microbial process thatconverts ammonia to nitrite and then nitrate. Elevated levels of nitratecan make the water unfit for human consumption. Nitrification is acommon occurrence in chloraminated potable water systems. Accordingly,water system operators spend large amounts of time attempting to preventor mitigate nitrification, mainly by closely monitoring and managingfree ammonia levels in the water supply.

Chloraminated water systems must be carefully monitored at multiplepoints in a water distribution network to appropriately detect the onsetof nitrification and portions of the water system are flushed to removewater with low disinfectant residual or elevated nitrite levels.Flushing not only wastes water and resources, the process is timeconsuming and can disrupt water supplies.

Many existing analysis and water treatment methods for use withchloramine disinfection do not contemplate that the chloramine treatedwater will be ingested by a human or will otherwise be used to providehydration to a biological system. Moreover, water may test as withinappropriate limits at a treatment plant, but as the water travels thoughthe water system, the chloramination level can change markedly,resulting in water that is either not adequately disinfected by the timeit exits the faucet of a consumer, or that exhibits an off-taste due tothe presence of di- or trichloramines.

Standard methods to measure monochloramine only are available. Themonochloramine can be determined amperometrically or titrated withferrous ammonium sulfate (FAS) using a colorimetric DPD (N,N Diethyl-1,4Phenylenediamine Sulfate) indicator under controlled conditions. Thesemethods are best used in a lab situation and require a higher degree ofskill and care to perform the analysis. Both methods require goodcontrol of the reagents added to limit dichloramine interference and canalso have interference from organic chloramines. Accordingly, thesestandard methodologies are generally not suitable to ongoing measurementwithin a municipal water delivery system, especially in regard toobtaining real time measurements of potable water that is in the processof being delivered to consumers.

Ammonia detection is also relevant in a municipal water distributionsystem. Because the presence of excess free ammonia greatly increasesthe risk of nitrification, efforts must be made to minimize free ammonialevels in chloraminated potable water systems. Free ammonia levels canbe measured with a variety of field and laboratory methods. However,many of the field techniques have reliability issues at the lowconcentrations that occur in properly functioning potable water systems,for example, generally below 0.1 mg/l.

In this regard, one secondary disinfectant control strategy uses a verysmall (ppb) free ammonia concentration to ensure that monochloramine isthe predominant species, with the goal to provide secondary disinfectionwithout creating the foul tasting di- and trichloraminated species. Ifthe free ammonia concentration is kept very low, the potential ofnitrifying bacteria developing in the distribution system is minimized.However, in practicality, the control of free ammonia at the low ppmrange, especially in the water distribution environment, is difficultbecause of other variables that affect the ability to accurately andclosely monitor such a low level of free ammonia in a large volume ofwater, especially when adding ammonia precisely to a large volume whilestill managing chlorine levels to remain within specification. If toomuch ammonia containing material is added, more chlorine will have to beadded, otherwise excess of ammonia will be present as a food source forthe nitrification process. If too much chlorine containing material isadded, di- or trichloramines can be created, and free ammonia will haveto be back added to reset the levels to 5:1 (by weight) or to 1:1 (bystoichiometry) required for monochloramine speciation. Alternatively,the systems will need be flushed, as discussed earlier.

Moreover, existing free ammonia analysis requires reagents that arecumbersome to deploy in field settings. The complexity of free ammoniatesting, coupled with the high stakes involved in ensuring safe potablewater for consumers, generally requires highly trained personnel toconduct the testing, a reality that further limits deployment of freeammonia analysis in the field. In short, today there is no free ammoniatest methodology that can provide truly accurate results when the testis conducted outside of a laboratory. As a result of these deficienciesin analysis techniques, water system operators have a difficult time inoptimizing and maintaining chloramine chemistry in potable watersystems, thus leaving water systems vulnerable to nitrification and/orover-chlorination or both.

Oxidation reduction potential (ORP) has been used to measure chlorine(and other oxidant) levels in water. Measurements of ORP in water canreflect the ability of certain chemical components in the water toaccept or lose electrons. In laboratory settings where ongoing electrodecalibration and process controls are available, ORP can exhibit highreliability. However, they are not used for analysis and treatment ofmunicipal water supplies or well water because of inaccuracies inherentin the measurements that can result from at least pH, temperature, andwater source effects (e.g., metals, CaCO₃, etc., that are present as afunction of the location where the water is sourced and/or the path ittravels during delivery to the consumer). The ORP electrodes themselvesare highly sensitive to deposits that affect ORP measurement kineticsand require frequent maintenance to remove buildup that occurs on theelectrode surface. While pH, temperature, dissolved materials andelectrode deposit effects that may affect ORP measurements can bereadily addressed in laboratory settings to enable the method to provideaccurate chloramination information, ORP cannot readily be deployed infield settings for the measurement and management of chloraminationdisinfection of municipal water supplies, especially in relation toestimation of the amount of free ammonia present in a water supply. Putsimply, ORP is not seen to be reliable in indicating chloraminationlevels in water systems. Therefore, this methodology is not deployed byhealth departments to evaluate safe disinfectant levels.

There remains a need for methods to better measure and managedisinfectant composition in municipal water supplies at locationsdownstream from water treatment facilities or in wells. Methodologies tomeasure and manage chloraminated speciation and free ammonia levels to amore controlled degree are also needed. There is also need for methodsthat can be deployed by technicians without sophisticated chemicaltraining and skills or that can be deployed inline using automatedprocesses.

SUMMARY OF THE INVENTION

In certain non-limiting embodiments, the present invention is directedto a method of determining a disinfectant composition of a municipalwater supply from a water sample that includes: (a) obtaining a watersample from a water source at a sampling location; (b) adding achlorine-containing material to the water sample in the presence of anoxidation reduction potential (ORP) measurement device; (c) generating aplurality of ORP measurements during addition of the chlorine-containingmaterial to the water sample; (d) estimating a concentration of one ormore of free ammonia, fully combined ammonia, monochloramine, or amixture of dichloramine and trichloramine in the water sample from whichthe estimation is derived based on the relationship between the addedchlorine material and the plurality of ORP measurements; and (e)determining a disinfectant composition of the water source at the watersampling location from the concentration calculation. Further, as to thestep of obtaining a water sample: (i) the water sample is derived from awater treatment facility; (ii) a chlorine-containing material and anammonia-containing material are present in the water source; and (iii)the sampling location is located downstream from the water treatmentfacility.

In some non-limiting embodiments, the concentration is estimated bymonitoring the rate of change of ORP measurement in millivolts as afunction of the amount of chlorine-containing material added to thewater sample. In addition, the concentration can also be estimated bycalculating a slope obtained by plotting the ORP of the water sampleversus the amount of chlorine-containing material added to the watersample. Moreover, the disinfectant composition is determined as areal-time measurement.

In certain non-limiting embodiments, the chlorine-containing material isadded to the water sample in a known volume while generating theplurality of ORP measurements to determine the relationship between theadded chlorine material and the plurality of ORP measurements. In somenon-limiting embodiments, the method further includes comparing theplurality of ORP measurements obtained from the water sample locateddownstream from the water treatment facility to ORP measurementsobtained from a water sample obtained at the water treatment facility todetermine disinfection efficacy. In certain non-limiting embodiments,the estimation provides the concentration of both free ammonia andmonochloramine in the water sample.

In some non-limiting embodiments, the method further includes, afterdetermining the disinfectant composition of the water source, addingadditional chlorine-containing materials and ammonia containingmaterials to the water source to achieve a desired level of thedisinfectant composition. Moreover, an amount of the added additionalchlorine-containing materials and ammonia-containing materials can beindependent of a concentration of the chlorine-containing materials andammonia-containing materials. In addition, in some non-limitingembodiments, a volume of the water sample obtained from the water sourceis known.

In certain non-limiting embodiments, the present invention is directedto a method of determining a free ammonia composition of a water supply.The method includes: (a) obtaining a water sample from a water supply ata sampling location; (b) adding a chlorine-containing material to thewater sample in the presence of an oxidation reduction potential (ORP)measurement device; (c) generating a plurality of ORP measurementsduring addition of the chlorine-containing material to the water sample;and (d) estimating a concentration of free ammonia in the water samplein which the estimation is derived from the relationship between theadded chlorine material and the plurality of ORP measurements.

In some non-limiting embodiments, the method also includes maintaining aconcentration of free ammonia in the water supply within a range ofgreater than 0 mg/L and less than about 0.1 mg/L. In addition, incertain non-limiting embodiments, the water sample is derived from awater treatment facility and the sampling location is located downstreamfrom the water treatment facility. The method of determining freeammonia composition can also be substantially free of a reagent otherthan chlorine and ammonia-containing materials.

In some non-limiting embodiments, the concentration of free ammonia isestimated from monitoring the rate of change of ORP measurement inmillivolts as a function of the amount of chlorine-containing materialadded to the water sample. Further, in some non-limiting embodiments,the method further includes adding additional chlorine-containingmaterials when the estimated ammonia concentration is above a desiredammonia concentration range.

In certain non-limiting embodiments, the present invention is directedto a system for maintaining the disinfectant level of a potable watersupply. The system can include: (a) a water quality assessment modulethat includes (i) a plurality of sensors comprising at least anoxidation reduction potential sensor (ORP), and (ii) a control module inoperational engagement with the plurality of sensors; (b) a water supplyintended for delivery of potable water to a consumer; (c) a watersampling device comprising a fluid delivery means configured to providea sample of water derived from the water supply to the water qualityassessment module; and (d) a chlorine feed source and an ammonia feedsource in which each of the sources are, independently: (i) inoperational engagement with the water quality assessment module; and(ii) in fluid communication with the water supply. Further, the systemis configured to measure and adjust the chloramination level and thefree ammonia levels of a portable water supply prior to delivery of thewater supply to the consumer.

In some non-limiting embodiments, the water quality assessment module isconfigured to provide information regarding at least a disinfectantlevel of the water supply. Further, the water supply can be maintainedin a water storage tank. In certain non-limiting embodiments, the waterstorage tank includes a mixing module.

In certain non-limiting embodiments, the water sampling device furtherincludes a pump. In addition, in some non-limiting embodiments, a volumeof the sample of water provided by the delivery means is known. Theplurality of sensors used with the system can also include a pH sensorand a temperature sensor.

The present invention is also directed to the following clauses:

Clause 1: A method of determining a disinfectant composition of amunicipal water supply from a water sample comprising: (a) obtaining awater sample from a water source at a sampling location, wherein: (i)the water sample is derived from a water treatment facility; (ii) achlorine-containing material and an ammonia-containing material arepresent in the water source; and (iii) the sampling location is locateddownstream from the water treatment facility; (b) adding achlorine-containing material to the water sample in the presence of anoxidation reduction potential (ORP) measurement device; (c) generating aplurality of ORP measurements during addition of the chlorine-containingmaterial to the water sample; (d) estimating a concentration of one ormore of free ammonia, fully combined ammonia, monochloramine, or amixture of dichloramine and trichloramine in the water sample, whereinthe determination is derived from the relationship between the addedchlorine material and the plurality of ORP measurements; and (e)determining a disinfectant composition of the water source at the watersampling location from the concentration calculation.

Clause 2: The method of clause 1, wherein the concentration is estimatedfrom monitoring the rate of change of ORP measurement in millivolts as afunction of the amount of chlorine-containing material added to thewater sample.

Clause 3: The method of clauses 1 or 2, wherein the concentration isdetermined by calculating a slope obtained by plotting the ORP of thewater sample versus the amount of chlorine-containing material added tothe water sample.

Clause 4: The method of any of clauses 1 to 3, wherein the disinfectantcomposition is determined as a real-time measurement.

Clause 5: The method of any of clauses 1 to 4, wherein thechlorine-containing material is added to the water sample in a knownvolume while generating the plurality of ORP measurements to determinethe relationship between the added chlorine material and the pluralityof ORP measurements.

Clause 6: The method of any of clauses 1 to 5, further comprisingcomparing the plurality of ORP measurements obtained from the watersample located downstream from the water treatment facility to ORPmeasurements obtained from a water sample obtained at the watertreatment facility to determine disinfection efficacy.

Clause 7: The method of any of clauses 1 to 6, wherein the estimationprovides the concentration of both free ammonia and monochloramine inthe water sample.

Clause 8: The method of any of clauses 1 to 7, further comprising, afterdetermining the disinfectant composition of the water source, addingadditional chlorine-containing materials and ammonia-containingmaterials to the water source to achieve a desired level of thedisinfectant composition.

Clause 9: The method of clause 8, wherein an amount of the addedadditional chlorine-containing materials and ammonia-containingmaterials is independent of a concentration of the chlorine-containingmaterials and ammonia-containing materials.

Clause 10: The method of any of clauses 1 to 9, wherein a volume of thewater sample obtained from the water source is known.

Clause 11: A method of determining free ammonia composition of a watersupply comprising: (a) obtaining a water sample from a water supply at asampling location; (b) adding a chlorine-containing material to thewater sample in the presence of an oxidation reduction potential (ORP)measurement device; (c) generating a plurality of ORP measurementsduring addition of the chlorine-containing material to the water sample;and (d) estimating a concentration of free ammonia in the water sample,wherein the estimation is derived from the relationship between theadded chlorine material and the plurality of ORP measurements.

Clause 12: The method of clause 11, wherein a volume of the water sampleobtained from the water source is known.

Clause 13: The method of clauses 11 or 12, wherein the water is derivedfrom a water treatment facility and the sampling location is locateddownstream from the water treatment facility.

Clause 14: The method of any of clauses 11 to 13, further comprisingmaintaining a concentration of free ammonia in the water supply within arange of greater than 0 mg/L and less than about 0.1 mg/L.

Clause 15: The method of any of clauses 11 to 14, wherein the method ofdetermining free ammonia composition is substantially free of a reagentother than chlorine and ammonia-containing materials.

Clause 16: The method of any of clauses 11 to 15, wherein theconcentration of free ammonia is estimated by monitoring the rate ofchange of ORP measurement in millivolts as a function of the amount ofchlorine-containing material added to the water sample.

Clause 17: The method of any of clauses 11 to 16, further comprisingadding chlorine-containing materials when the estimated ammoniaconcentration is above a desired ammonia concentration range.

Clause 18: A system for maintaining the disinfectant level of a potablewater supply comprising: (a) a water quality assessment modulecomprising: (i) a plurality of sensors comprising at least an oxidationreduction potential sensor (ORP); and (ii) a control module inoperational engagement with the plurality of sensors; (b) a water supplyintended for delivery of potable water to a consumer; (c) a watersampling device comprising a fluid delivery means configured to providea sample of water derived from the water supply to the water qualityassessment module; (d) a chlorine feed source and an ammonia feedsource, wherein each of the sources are, independently: (i) inoperational engagement with the water quality assessment module; and(ii) in fluid communication with the water supply, wherein the system isconfigured to measure and adjust the chloramination level and the freeammonia levels of a potable water supply prior to delivery of the watersupply to the consumer.

Clause 19: The system of clause 18, wherein the water quality assessmentmodule is configured to provide information regarding at least adisinfectant level of the water supply.

Clause 20: The system of clause 19, wherein the water supply ismaintained in a water storage tank.

Clause 21: The system of clause 20, wherein the water storage tankincludes a mixing module.

Clause 22: The system of any of clauses 18 to 21, wherein the watersampling device further comprises a pump.

Clause 23: The system of any of clauses 18 to 22, wherein the volume ofthe sample of water provided by the delivery means is known.

Clause 24: The system of any of clauses 18 to 23, wherein the pluralityof sensors further comprise a pH sensor and a temperature sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a method of determining disinfectant composition ofpotable water by measurement of ORP; and

FIG. 2 illustrates an exemplary system in which the inventivemethodology can be implemented.

DESCRIPTION OF THE INVENTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof, and within which areshown by way of illustration certain embodiments by which the subjectmatter of this disclosure may be practiced. It is to be understood thatother embodiments may be utilized and structural changes may be madewithout departing from the scope of the disclosure. In other words,illustrative embodiments and aspects are described below. It will, ofcourse, be appreciated that in the development of any such actualembodiment, numerous implementation-specific decisions must be made toachieve the developers' specific goals, such as compliance withsystem-related and business-related constraints, which may vary from oneimplementation to another. Moreover, it will be appreciated that suchdevelopment effort might be complex and time consuming, but wouldnevertheless be a routine undertaking for those of ordinary skill in theart having the benefit of this disclosure.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as is commonly understood by one of ordinary skillin the art to which this disclosure belongs. In the event that there isa plurality of definitions for a term herein, those in this sectionprevail unless stated otherwise.

Wherever the phrases “for example,” “such as,” “including,” and the likeare used herein, the phrase “and without limitation” is understood tofollow unless explicitly stated otherwise.

The terms “comprising” and “including” and “involving” (and similarly“comprises” and “includes” and “involves”) are used interchangeably andmean the same thing. Specifically, each of the terms is definedconsistent with the common United States patent law definition of“comprising” and is therefore interpreted to be an open term meaning “atleast the following” and is also interpreted not to exclude additionalfeatures, limitations, aspects, etc.

The term “about” is meant to account for variations due to experimentalerror. All measurements or numbers are implicitly understood to bemodified by the word about, even if the measurement or number is notexplicitly modified by the word about.

The term “substantially” (or alternatively “effectively”) is meant topermit deviations from the descriptive term that do not negativelyimpact the intended purpose. Descriptive terms are implicitly understoodto be modified by the word substantially, even if the term is notexplicitly modified by the word substantially.

“Water supply” as used herein means water generated from a municipalwater supply, a well system or both.

The term “disinfectant composition” comprises the amounts of one or moreof free ammonia, fully-combined ammonia, monochloramine, dichloramine,trichloramine, or free chlorine that is present in the water supply.Disinfection composition can be estimated from a water sample derivedfrom the water supply as discussed elsewhere herein.

The term “municipal water supply” means a water supply provided from acentral point and piped to individual users under pressure. Watersources used to generate municipal water supplies can vary. As requiredby regulations, municipal water supplies will undergo primarydisinfection to make it suitable for use as potable water at thetreatment facility. Secondary disinfection with chloramination processeswill also be provided at the water treatment plant to ensure that thewater will remain suitable for use as potable water as it travelsthrough the water system to the consumer.

“Well water” is water obtained from a below-ground water source such asan aquifer, and that is stored (or storable) for supply as potablewater, among other uses. As would be recognized, well water can nativelycomprise free ammonia as a result of natural processes. Well water mayor may not be disinfected prior to use.

In certain non-limiting embodiments, the present invention comprises amethod of determining disinfectant compositions in potable water atlocations in a municipal potable water supply that are locateddownstream from a water treatment facility. In this regard, the presentinvention relates to maintaining adequate secondary disinfection of apotable water supply, where “secondary disinfection” means themaintenance of free or combined chlorine levels in a water supply oncethe water is treated with primary disinfecting methods (e.g.,sedimentation, coagulation, UV, chlorine gas, etc.). Yet further, thepresent invention relates to systems in which the disinfectant leveldetermination can be implemented.

As would be recognized, “primary disinfectants” are intended to kill orotherwise deactivate pathogens that exist in a water source upon itsarrival at a treatment plant, whereas “secondary disinfectants” areintended to maintain the healthiness and cleanliness of the water supplyupon leaving the treatment plant throughout its path through a municipalwater system until it reaches the faucet of a consumer.

The present invention relates, in some non-limiting embodiments, toestimating, maintaining, and adjusting the secondary disinfectantcomposition of potable water supplies where the secondary disinfectionis provided in part or in full by way of chloramines. Disinfectioncomposition is estimated and/or maintained by measuring the presence (orlack thereof) of a disinfecting species of interest using an ORPelectrode as discussed elsewhere herein. In this regard, at the watertreatment plant, for secondary disinfection, chlorine or achlorine-containing material will be added to the water supply. Ammoniaor ammonia-containing materials will also be added to the water supplyduring treatment, usually after addition of the chlorine-containingmaterial, when secondary disinfection is to be effected and maintainedby chloramination, as in the present invention. Note that, while ammoniais generally added to water supplies to provide suitable secondarydisinfection with chloramines, some ammonia-containing materials may benaturally present in the water source when it reaches the treatmentfacility. Such naturally occurring ammonia material, which will varyfrom water source to water source, will be included in the discussionsrelated to free ammonia detection herein.

During one or more periods in the water distribution timeline and/or atone or more locations in the water distribution network, the amount ofone or more of the disinfectant compositions of interest can beestimated by measuring the ORP of the sample during addition of chlorine(or a chlorine containing material) to the water sample. The amount ofdisinfectant composition of interest in the water sample can then beestimated from one or more of previously identified dose responsecurves, as discussed further herein.

In some non-limiting embodiments, the present invention relates todevices and methods to estimate the free ammonia concentration in awater supply by extrapolating concentrations estimated from a watersample obtained from the water supply. The free ammonia estimation canbe generated after the water leaves a water treatment facility and priorto delivery of the water to a consumer, where the sampling is taken atone or more locations in the water distribution network and/or atdifferent times. The present invention allows a water supply to besampled and tested for free ammonia levels using simple and reliabletesting methodologies, in particular, ORP measurement of a water samplederived from the water supply of interest. The ammonia estimation of thepresent invention can also be conducted on water that has not previouslybeen treated in a primary disinfectant regime, such as water sourcedfrom or otherwise present in a well, where free ammonia may be nativelypresent therein.

ORP can be used to determine or estimate the levels of chemicaldisinfectants that work via the oxidation or reduction of the structuresof microbial contaminants. For example, chlorine, an oxidant, will stripelectrons from the negatively charged cell walls of some bacteria, thusrendering it harmless to the potable water consumer. The inventors havefound that because ORP suitably measures the total chemical activity ofa solution—which in the present invention correlates to a disinfectingspecies composition—ORP as described herein can estimate the totalcomposition of all, or substantially all, oxidizing and reducingdisinfectants in solution. While in the case of the present invention,the level of chloramines (e.g., mono-, di- and tri-) are of primaryrelevance, other oxidants that may be used in water to act in a redoxcapacity to inactivate harmful materials in water are also analyzableaccording to the ORP methods and devices herein: hypochlorous acid,sodium hypochlorite, UV, ozone, peracetic acid,bromochlorodimethylhydantoin, etc.

When other factors in a water sample are substantially stable(temperature, pH, etc.), ORP values are related to disinfectantcomposition in a water sample and, therefore, the water supply fromwhich the sample is derived. As the concentration of chlorine-containingmaterial, for example, chloramine species, in a water sample changes,the ORP value changes. Accordingly, ORP has been found to provide areliable estimation of disinfectant composition in a water sample thathas been subjected to a chloramination disinfection methodology.

In some non-limiting embodiments the present invention substantiallycharacterizes a disinfectant composition in a water sample, as opposedto being a direct detection method of a particular chemical or chemicalspecies. That is, ORP indicates the effectiveness of those disinfectantmaterials that work through oxidation and reduction. Use of this methodby itself cannot generally determine the exact concentrations of knownspecies of chemical in solution without collection of additionalinformation. However, when applied to test previously treated municipalwater supplies, the regulatory regimes applicable to municipal watersupplies greatly restrict the types and amounts of chemicals andchemical species that may be present in potable water. Moreover, since,in some non-limiting embodiments, the water samples evaluated herein arederived from water supplies emanating from water treatment facilities,any ORP measurements can be used to not only estimate the disinfectingcomposition of a water sample, and, thus, the municipal water supplyitself at the point of testing, but also to confirm the type and amountof a sanitizing chemical that is providing the secondary disinfection tothe potable water in real time.

The present invention can also be used to estimate the free ammoniaconcentration of untreated water, such as well water. In this regard,chlorine (or chlorine-containing material) is added to a water sampleobtained from a water supply and the dose response curve is used togenerate a concentration estimation.

The present invention allows ORP to be deployed to test secondarydisinfection species composition in municipal water supplies to obtainreal time, online measurements. Such real time, online measurementsrepresent a substantial advance in the management of municipal potablewater supply systems. That is, water systems operators have historicallybeen challenged to guarantee to potable water consumers that potablewater maintains its safety once it leaves the water treatment facility.

The complexities required to obtain accurate analysis of water hasgenerally required samples to be taken from water sources for analysisunder laboratory conditions. Such complexities are exacerbated by thesmall quantities of materials that must be quantified to ensure thatpotable water is safe and complies with the extensive regulatoryregimes. The present invention greatly simplifies the analysis, and,therefore, provides heretofore unavailable economies and ease ofdeployment in the field to provide “just in time” knowledge about thedisinfectant composition of a municipal water supply as the watertravels through the distribution network from the water treatment plantto the consumer. Still further, the present invention enables theautomated optimization of chloramine disinfectant composition andconcentration in the water distribution system, where such automation isdiscussed elsewhere herein. Yet further, the present invention providesan improved methodology to estimate free ammonia composition in watersupplies, where such knowledge is of interest in determiningnitrification potential of the water supply from which the water sampleis derived.

As used herein, “substantially accurate estimation of disinfectantcomposition in potable water” means the ability to distinguish betweenpotable water with excess free ammonia and potable water with excess di-or trichloramine species, as well as free chlorine, if the system hasmoved past the chlorine breakpoint, as such materials and terms areknown to those of ordinary skill in the art.

Still further, the present invention provides a previously unavailablemethodology to enable water supply operators to maintain the secondarydisinfection regime substantially at all times in the water deliverynetwork in the monochloramine species part of the speciation curve. (SeeFIG. 1). Yet further, the present invention allows substantially precisecontrol of the monochloramine disinfectant regime so as to allow theamount of free ammonia in a potable water supply to be maintained withinthe desired range of from greater than 0 mg/L to less than about 0.1mg/L, where such range is the optimum for managing chloraminatedsystems. In short, the present invention provides effectivechloramination disinfection while still reducing the potential for thechloraminated water supply to undergo nitrification, as discussedhereinafter.

In use, a technician can manually obtain a sample of water from alocation downstream of the water treatment facility, that is, after thewater has undergone primary disinfection and is in the process of beingdelivered to consumers for use. Alternatively, an automatic inlineprocess can be used to sample the potable water after it leaves thetreatment facility. The locations where the water can be sampled fordisinfectant composition are expansive, however, it may generally bemore suitable to test in locations where the water collects for storageor is otherwise staged for delivery. In this regard, if it is determinedthat the potable water is out of compliance for disinfectioncomposition, the stored or collected potable water can be treated inthat location or, if necessary, diverted so that the out-of-compliancewater is not delivered to the consumer. In some non-limitingembodiments, the water is sampled at or near a water storage tank orwater storage location that is downstream from the water treatmentfacility. Water can also be manually or automatically sampled from awell source.

The relevance of free ammonia to disinfectant composition in watersystems where secondary disinfection includes chloramination hasincreased the availability of free ammonia sensors in recent years.Notably, existing free ammonia estimate techniques require the use ofadditional reagents. The use of reagents that must be stored, measured,and re-supplied greatly increases the complexity of free ammoniameasurements. Thus, the ability to easily estimate the amount of freeammonia in a water sample derived from a municipal water supply, as inthe present invention, provides significant benefits. In somenon-limiting embodiments, the methodology of the present invention issubstantially free of a reagent besides chlorine and ammonia-containingmaterials because ORP probes used, according to the description herein,use an electrical circuit to generate the measurements. The substantialabsence of reagents needed to generate free ammonia estimation using thepresent invention is a marked improvement over existing methodologies.Still further, free ammonia estimation, according to the presentinvention, does not require concurrent determination of themonochloramine concentration using colorimetric determination in orderto obtain an estimation of the amount of free ammonia in real-time.

Nitrification is the two-stage biological process of converting ammoniafirst into nitrite and then into nitrate. Nitrification can occur inpotable water systems containing natural ammonia, in chloraminatedsystems where free ammonia exists in excess from the chloraminationprocess, or from decomposition of the chloramines themselves. Elevatedlevels of nitrate can be harmful and, thus, reduction or elimination ofnitrates is a desirable outcome for municipal water supply managers.Because chloraminated water disinfection necessarily gives rise to thepossibility of nitrification, it is desirable to maintain the amount offree ammonia present in a potable water supply as low as possible, whilestill providing a small amount. A carefully controlled amount of totalchlorine to total ammonia is, therefore, necessary. Moreover, even iffree ammonia is absent when the water supply leaves the water treatmentplant—where chemical dosing and detection methodologies can be moreclosely monitored and controlled—free ammonia can be released as thewater travels to the customer as the disinfectant attacks bacteria orreacts with organics that generally exist in any distribution system.The released free ammonia acts as a food source for nitrifying bacteria.This can lead to nitrification and biofilm re-growth in the distributionsystem. The nitrification and biofilm re-growth process consumes theeffectiveness of disinfectants and can lead to corrosion in thedistribution system. Beyond the health and regulatory issues, customertaste and odor complaints can result directly from nitrification or fromfree chlorine reversions used to treat the issue. If uncontrolled,costly and disruptive line flushes may be required. In this regard, itis beneficial to be able to accurately and easily estimate free ammonialevels after the water leaves the treatment plant.

In certain non-limiting embodiments, therefore, the present inventionalso comprises methods and devices for detecting the presence andrelative amounts of free ammonia in a water sample derived from a watersupply of interest. The present invention also provides methods anddevices to reduce nitrification risk of water in municipal watersupplies. Yet further, the present invention provides a nitrificationrisk factor that allows municipal water supply operators to assesswhether nitrification is likely to happen in their system.

The present invention allows a substantially direct estimation of thefree ammonia species present in a water sample, so as to substantiallyeliminate the need to overshoot the monochloramine part of the curve togenerate knowledge of whether and how much free ammonia was present inthe water sample before addition of the chlorine (or chlorine containingspecies). Such ability to directly estimate free ammonia present inpotable water provides a significant advance over existing methodologiesto inline treat water supplies in secondary disinfection regimes.

In particular, the present invention allows inline direct estimation ofthe free ammonia content of a water supply in situ by use of ORP doseresponse curves generated for a plurality of free ammoniaconcentrations, monochloramine, di- and tri-chloramine concentrations,pHs, and temperatures of relevance in water supplies, including but notlimited to municipal water supplies and well water. The various doseresponse curves can then be used in an inline process whereby a watersample is automatically pulled from the water supply and chlorine (or achlorine-containing material) is titrated therewith in the presence ofan ORP electrode. The resulting ORP electrode response upon addition ofthe chlorine-containing material is then compared to the correspondingORP dose response curve, so as to provide an estimation of the amount offree ammonia present in the water supply.

In some non-limiting embodiments, the present invention allows a watersupply operator to detect the real-time condition of a water supply inrelation to the amount of free ammonia present. This, in turn, providesan improvement in the ability to substantially maintain the amount offree ammonia in a water supply to the optimum range of greater than 0mg/L to about 0.1 mg/L.

In particular, free ammonia in chloraminated systems cannot readily bedetermined by traditional total ammonia methods. Traditionalcolorimetric methods for ammonia such as the phenate, salicylate, andthe other methods, suffer to various degrees from interference due tomonochloramine, dichloramine, or organic chloramines. The level ofinterference in these methods depends on the chloramine concentration,the form of the organic chloramines present and the uniquecharacteristics of the method being used. This means that chloraminelevel must also be determined so that the value can be subtracted out ofthe free ammonia detection results.

Should the real time ORP measurements indicate that the amount of freeammonia present is above the desired range, chlorine (orchlorine-containing materials) can be added using known methods. If thechlorine residual concentration needs to be increased or “boosted” tomaintain a safe disinfectant level throughout the remainder of thedistribution system, chlorine can be added. Either of these additionscan be done at elevated water tanks, storage reservoirs, entrances toconsecutive systems, or at selected points in low residual ortroublesome sections in a distribution system. Feeding chlorine (orchlorine-containing material) and ammonia (or ammonia-containingmaterial) in the specified ratio forms additional chloramines, therebyproviding the necessary secondary disinfection to ensure safe and goodtasting water for consumers. Such feeding can be conducted usingautomatic methods that provide inline treatment.

The chlorine (or chlorine-containing material) addition levels can bedetermined by standard volumetric addition calculations. When the wateris present in a storage container, such as a water tank, thecalculations are conducted to apply the chlorine (or chlorine-containingmaterial) in batch form. When the chlorine (or chlorine-containingmaterial) is added to a water pipe while the water is flowing therein,process control addition processes can be used. For example, a pipe with1000 liters per minute of flow would need 1 g/min of chlorine additionto achieve a residual disinfectant raise of 1 mg/l.

Alternatively, should the real time ORP measurements indicate that freeammonia is not detectable, it will then be apparent that thechloramination disinfection regime has moved from monochloramine to di-or trichloramine region, or even past the chlorine breakpoint region.

To generate an ORP measurement of the water sample, from which thedisinfectant composition of the potable water supply can be determined,the water sample to be tested is placed in the presence of an ORPsensor, such as an ORP electrode. The oxidant, that is, the chlorine (orchlorine-containing material) is added to the water sample, where theoxidant has a known concentration. The ORP measurement device provides aresponse that is measured in millivolts, and it is this dose responserelationship that is plotted to generate data from which the chemicalmaterials of interest and amounts thereof can be derived.

Testing of water supply using ORP involves, for example, introducing anoxidant into the sample in a known volume and following the change inelectro-chemical potential resulting from the oxidant addition. The ORPmeasurement apparatus will follow the electrochemical potential signalgenerated from the oxidant addition. In regard to chlorine as theoxidant, the stoichiometry of the chloramine reaction states that onepart of chlorine reacts with one-part ammonia on a molar basis (or 5:1ratio on a weight basis).

ORP electrodes and attendant reporting componentry are available from awide variety of suppliers, for example, Myron L Company's 720 Series ofmeasurement devices.

Moreover, unlike with other ORP methodologies, the robust methodologyherein substantially does not require ORP electrodes to be preciselymaintained to ensure that results provide accurate estimations ofdisinfectant composition of a municipal water supply. In this regard,baseline ORP measurements can be taken as the treated water (that is,water that has undergone primary disinfection) leaves the treatmentfacility. ORP measurements can be taken at one or more locations in thewater distribution network (that is, at a water storage tank, etc.), andthose results compared to the results at the water treatment plant toobtain an estimation of whether the water sample, and, therefore, thewater supply that is evaluated downstream from the water treatmentfacility maintains suitable disinfection efficacy. In short, the pH,temperature, and dissolved salt content of the water will not changemarkedly from the point that the water leaves the treatment plant untilit reaches the consumer. Indeed, if these characteristics of the waterdid change, the water system could be experiencing significant failurethat would go beyond the need to estimate disinfectant composition.Thus, the inventors have found that reliable ORP measurements can beobtained within a single water system as described herein.

While ORP electrodes may generate buildup of residue and/or memoryeffects over time, those effects will be gradual. Therefore, comparisonof results from hour to hour or day to day or week to week or even monthto month have been found by the inventors to be fairly reliable.Moreover, any measurements that are affected by changes in the ORPelectrodes over time can also be measured and disinfectant compositionestimations adjusted in relation thereto. This means that the ORPmeasurement device can either remain in the field for use and/or bedeployed for an extended time period within a municipal water systemdistribution network substantially without maintenance.

The inventors herein have further determined, in some non-limitingembodiments, that valuable information about the disinfectantcomposition of a water supply that is downstream from a water treatmentfacility can be obtained by estimating the presence (or absence) ofchemicals relevant to disinfection, as opposed to generating precisemeasurements of such chemicals. Notably, potable water analysis hastraditionally been directed toward finding the actual chemical makeup,including amounts, in order to comply with regulatory requirements, aswell as to provide safe water to consumers. The inventors herein haveidentified a way to ensure that water that is compliant and safe inrelation to sanitization level when it leaves the water treatmentfacility and remains so as it travels through the water distributionnetwork on its way to the consumer, namely by using ORP to estimate thedisinfection level of the potable water. Such estimation provides “goodenough” information about disinfectant composition, and the simplicityof the methodology herein relative to other methods of measurement usedhistorically, enables cost effective real time measurement ofdisinfectant composition. Moreover, the use of ORP is highly suitablefor estimation of the disinfectant composition of chloraminated systemsas described in detail herein.

In certain non-limiting embodiments, the present invention is used tomeasure chloramination levels and/or free ammonia levels of potablewater, that is water intended for ingestion by humans. Yet further, thepresent invention consists essentially of measuring the chloraminationlevels and/or free ammonia levels of potable water. Still further, thepresent invention is substantially not used to measure the levels offree chlorine in potable water.

Additionally, the robust methodology herein allows comparison of resultsfrom different water supplies to be compared in an “apples to apples”framework, such that the disinfectant composition of different watertreatment regimens or scenarios can be evaluated both within a singlemunicipal water system (e.g., different locations downstream from thewater treatment plant) or among different municipal water systems (e.g.,different cities in a regulatory jurisdiction). Widespread deployment ofORP to estimate disinfectant composition of a water system may serve toimprove the evaluation of potable water quality generally. Suchimprovements are enhanced by use of the inventive ORP methodology inwater systems as discussed in more detail hereinafter.

Referring to FIG. 1, addition of chlorine (or other oxidants) to thewater sample results in a change in millivolts, as measured by aproperly configured ORP electrode. In FIG. 1, the chlorine additionregime is presented in relation to evaluating and, in some non-limitingembodiments, adjusting the chloramination and/or free ammonia levels ofpotable water. In the section denoted “A”, addition of chlorine will bein the form of salt formation and combination of chlorine with organicmaterials in the water. As such, the section denoted “A” will providesubstantially no disinfection efficacy because the chlorine is notavailable to provide disinfecting activity. Practically speaking, in asecondary disinfection regime, at least some chlorine should be presentin the water sample because of an addition in the water treatment plant,that is, in the primary disinfection regime. Accordingly, ORPmeasurements in the present invention will be with reference to pointslater in the plot after “A.”

In accordance with a desired secondary disinfection regime, detection offree ammonia in relation to generation of a suitable disinfectionactivity with no foul tasting di- and trichloramine formation will berelevant primarily in the point just to the left of the point marked“X.” This can be termed as the “sweet spot” for chloraminateddisinfection systems, that is, where the optimum stoichiometry ofchlorine to ammonia of substantially equal to 1:1 molar ratio isobtained. At this point, there will be substantially no free ammoniapresent—and, thus, substantially no nitrification potential—andsubstantially all monochloramine species will exist as thechloramination disinfecting species. When a threshold level ofadditional chlorine containing material is added, the dichloramine and,at higher chlorine concentrations, trichloramines (collectively denoted“C”) will become the predominant chloraminated species. While thesematerials have some disinfecting capabilities, they are sour smellingand tasting, and, thus, signal to consumers that their potable water isnot high quality. Free ammonia will be absent to the right of thesection denoted “B.”

Moreover, since monochloramine requires significantly less chlorine togenerate, the presence of di- and trichloramines signify that the watersystem operators are using more chlorine than necessary to achievedisinfection composition. Thus, the present invention also suitablyallows water system operators to manage the amount of chlorine they areusing in secondary disinfection regimes. When the amount of chlorinereaches the “breakpoint,” that is, where the chlorine is no longercombined with ammonia, chlorine will be present in the water samplesubstantially as free chlorine, Cl₂ (denoted as “D”). As would berecognized, free chlorine is largely undesirable in modern watertreatment systems because of the propensity of undesirable chlorinatedcompounds to be developed. Moreover, the presence of free chlorine in asecondary disinfection regime also signifies that a great excess ofchlorine is present in the water supply. Again, the ability to readilydetect the presence of chlorine in a water sample extracted from a watersupply using ORP greatly simplifies management of chlorine addition anduse in secondary disinfection regimes.

In accordance with the detection regime of the present invention, thedisinfectant composition represented by monochloramine present in thewater sample, and, thus, in the water supply at the point where thewater sample is taken, can be determined by evaluating the slope of thecurve generated by plotting the relationship—that is, the doseresponse—between added chlorine and ORP measurement, as presented inmillivolts. The change from monochloramine to dichloramine will beapparent when there is a change in the slope of the curve, as denoted by“X” on FIG. 1. At that point, the added chlorine will combine with themonochloramine to create di- and trichloramines Thus, measured chlorineresidual will decrease, and the ORP measurement will change because theredox reaction is changing. It is this change that allows determinationof the disinfectant composition of the water sample, and, thus, thewater supply at the location from which it was extracted.

The free ammonia level can also be generated from the ORP curvesgenerated for a water sample. The point just before this slope change atX will comprise only a small amount of ammonia (more than 0 mg/L) andless than about 0.1 mg/L.

Moreover, the pH, temperature, and dissolved salts are unlikely tochange markedly from hour to hour or day to day or week to week withinthe same municipal water supply. Thus, any pH, temperature and dissolvedsalt effects between and among measurements are likely to be very small,or at least small enough to not substantially reduce the accuracy of themeasurements within the time scales relevant to ensuring disinfectantcomposition of a municipal water supply. Notably, the recognition thatpH, temperature, and dissolved salt effects, while highly influential tolaboratory use of ORP, do not practically affect the viability of ORP inevaluating municipal water supplies or in well water in real time, orsubstantially in real time, represents a marked improvement in potablewater quality evaluation. In the present invention, pH and temperaturecan be measured concurrently with an ORP measurement, however, such pHand temperature measurements are typically used to confirm that thewater sample has consistent qualities to a first water sample obtainedfrom the same water source. For example, if a pH measurement of a firstwater sample is 7.1, but the subsequent water sample taken from the samewater source is 8.5, then it may be indicated that some type ofcontamination occurred in the water source as it traveled through thewater distribution system. Wide variations in pH and temperature canalso affect the estimation values, and are relevant to measure.Nonetheless, in most real use circumstances the pH and temperatures ofthe water supply will not vary substantially between water samplemeasurements.

In further non-limiting embodiments, the present invention providesmethodologies to estimate the level of residual chlorine-containingmaterial, in the water sample, and, therefore, the water supply fromwhich it is derived, where residual chlorine-containing materialcomprises monochloramine, dichloramine, trichloramine, and, in somecases, free chlorine. The chemical identities of these materials areprovided by evaluating slope changes in the curve resulting fromplotting the relationship between added chlorine and ORP measurements.

While the ORP methodology disclosed herein provides benefits when usedindependently, further utility is found when the invention isincorporated in an overall water monitoring and treatment system, suchas would be relevant with a municipal water supply system or a well. Inthis regard, the improved chloramination and free ammonia measurementsystem allows substantially real-time measurement of chloraminationlevels to enable water system operators to better ensure that water isnot just safe and compliant when it is initially treated in a watertreatment facility, but that it remains safe and compliant when it isdelivered to consumers. Yet further, the system herein can allowbaseline free ammonia levels to be determined in well water, and providedisinfection thereof. Whether used on municipal water supplies or onwell water, the methodology herein substantially reduces the likelihoodthat nitrification of previously chloraminated water will occur,enabling improved measurement and control of free ammonia levels inwater. In sum, the various aspects of the present invention allow watersystem operators to set and maintain consistent disinfectant levels inwater supplies, as well as allowing them to substantially eliminatecostly and labor intensive manual disinfectant testing and adjusting.

In certain non-limiting embodiments, the present invention allows watersystem operators to monitor and, therefore, treat and maintain, waterquality substantially without an attendant monitoring the concentrationsof the feed source, namely chlorine and ammonia. This allows thechlorine and ammonia to be stored in high concentrations for extendedperiods substantially without an attendant monitoring the concentrationof the material. Operators are able to add chlorine or ammonia to awater supply, for example, a water tank, and to determine theappropriate additional level of chlorine or ammonia by examining the ORPdose response readings. In this regard, the present invention furthercomprises a system to treat a water supply comprising adding one or moreof chlorine and ammonia to the water supply and measuring the ORPbehavior using an ORP electrode, where the additional levels aredirected by observing the ORP electrode behavior.

In this regard, the ORP dose response curve of FIG. 1 can be used todefine the addition of chlorine or ammonia to the water supply. Notably,the ORP behavior of the water sample will allow the operator to know theeffective disinfectant level of the water supply. Addition of a chlorineor ammonia source to that sample will be in relation to the known doseresponse behavior that is substantially independent of the concentrationof the chlorine or ammonia being added. To provide appropriateadjustment of the water supply, the operator need only know theapproximate volume of the water supply to which the multiple of thechlorine or ammonia needs to be applied to generate approximately thesame dose response for the water supply. For example, a chlorine feedsource added to a water sample of 1 L provides a dose response thatindicates that 0.5 ml of chlorine needs to be added to generate anappropriate level of monochloramination, and the total volume of waterin the water supply, such as in a water tank, is 500,000 L, the operatorcan add 0.5 ml*500,000 L=2.5 L of chlorine to the water supply to obtainthe desired level of disinfectant. This aspect of the present inventionpresents a substantial improvement over prior art methods that requireprecise dosing of a known concentration of chlorine to achieve anappropriate level of disinfection of a water supply.

Referring to FIG. 2, an exemplary configuration of a disinfectantmanagement system 200 in accordance with an implementation of thepresent invention is illustrated therein. System 200 comprises variousaspects, including a plurality of sensors 205 configured to generate atleast ORP measurements. Other sensors 205 that can be used with thesystem 200 include sensors to generate pH measurements and/ortemperature measurements. Additional sensors can be included in theplurality of sensors 205, where such additional sensors can beconfigured to provide measurements of free chlorine, total chlorine, andthe like.

System 200 also includes control module 210 configured with software andhardware. The combination of the plurality of sensors 205 and controlmodule 210 provides a water quality assessment module 215.

As would be understood, the plurality of sensors 205 are in operationalcommunication with the hardware and software aspects of control module210. In use, water quality assessment module 215 allows a water systemoperator to monitor, control, and generate data about a water systemunder management as a substantially integrated system.

Water quality assessment module 215 can be operated on a wide variety ofhardware devices including, but not limited to, PCs, tablets, mobiledevices, etc. Software operations, which will include various algorithmsassociated with system 200 and the various components therein configuredwith use therein, can be maintained in the cloud on a remote server, orthey can be operated using software that is natively installed on orused in conjunction with system 200. As such, suitable microprocessorand computer controls are incorporated into system 200 herein to enableoperation of system 200 in accordance with the inventive methodologyherein. In further non-limiting embodiments, system 200 can beconfigured to transmit real time data to water system managers and/ortechnicians who may be remote from system 200 via cellular, Wifi,Bluetooth® communication, or the like.

The integration of the various aspects associated with maintaining waterquality in accordance with the invention herein allows operators toprogram the various parameters associated with maintaining a suitabledisinfection level/composition of chloraminated water supplies, freeammonia determination in water supplies, and, optionally, other waterquality characteristics. Still further, the integration of the variousaspects herein allows an operator to continuously or periodicallymonitor and treat water quality data generated from water qualityassessment module 215.

In use, a water sample (not shown) is collected via a sample line 220from water supply 225, which is in a water tank 240 in FIG. 2. Sampleline 220 is operationally engaged with a pump (not shown) and watersample delivery means (not shown), for example, a pipe or tube or hoseto direct the water sample to the plurality of sensors 205, which inpertinent part includes at least an ORP sensor (not shown) and,optionally, a pH sensor (not shown) and a temperature sensor (notshown). Water quality assessment module 215 is configurable to activatethe pump (not shown) so as to provide a suitable volume of water sampledfrom water supply 225. If the water sample is found to have adisinfectant level or free ammonia level outside of a desired set point,control module 210 will provide instructions to at least one of chlorinefeed source 230 or ammonia feed source 235 to add suitable material soas to maintain uniform and consistent water quality within water supply225. While system 200 can be utilized in any municipal water supplyconfiguration, FIG. 2 illustrates a water supply 225 contained in awater storage tank 240.

As shown in FIG. 2, chlorine feed source 230 and ammonia feed source 235are in fluid communication with water supply 225 contained in water tank240 via chlorine injection line 245 and ammonia injection line 250,respectively. Chlorine feed source 230 and ammonia feed source 235 arein operational communication with the respective injection lines 240 and245 as shown by 255 and 260, respectively. Further, as shown in FIG. 2,chlorine injection line 245 and ammonia injection line 250 eachterminate in chlorine injection nozzle 265 and ammonia injection nozzle270, respectively. Alternatively, chlorine injection line 245 andammonia injection line 250 can be joined via a connection point (notshown) and the respective chemical injection can be provided by a singlechemical injection nozzle (not shown).

In use, the water quality assessment module 215 can be configured tomonitor disinfectant level of water supply 225 via periodic orsubstantially continuous collection of a plurality of water samples (notshown) via sample line 220, where at least a portion of each watersample is provided to one or more of the sensors (not shown) of theplurality of sensors 205. In some non-limiting embodiments, each watersample is evaluated by each of the sensors in plurality of sensors 205in each water sampling event. Yet further, only some of the sensors inplurality of sensors 205 are used in each water sampling event. Forexample, the disinfectant level related sensors in plurality of sensors205, namely ORP, pH, and temperature sensors (not shown) can be used onan ongoing basis (that is, substantially continuously or periodically),and other sensors included in plurality of sensors 205 can be used lessfrequently.

A notable improvement in system 200 over prior art systems is that realtime or substantially real-time information about the disinfectantcomposition of water supply 225 can be provided, or historical data canbe generated, maintained, and evaluated. In addition, water quality datafrom other sources, such as manual samples, can be inputted into thesystem to provide a comparison and archive of multiple measurementmethods. This allows water system operators and managers to collect dataon the quality of the water within the system 200 for any duration oftime from minutes to years. Such data allows water system operators toevaluate day to day operations, react to unexpected changes in waterchemistry, and observe the effects of treatment plant changes ondistribution system water quality.

In particular, chlorine feed source 230 and ammonia feed source 235 areeach independently configured to inject disinfectant materials intowater supply 225. As noted, control module 210 provides instructions foraddition of chlorine and/or ammonia via operational communication 260and 265, which can be wired or wireless. Water quality assessment module215 is accordingly configured to monitor the system via the plurality ofsensors 205 so as to provide pertinent information regarding at leastthe disinfectant level of water supply 225 in system 200, includingproviding alarms or other signals to an operator, if needed. In thisregard, system 200 is configured to alert the user of any irregularitieswithin the system and produce an automated response, from an alert onthe screen to system shut down, in order to ensure safe operatingconditions. System 200 further incorporates a drain 275 in operationalcommunication with water quality assessment module to allow removal ofthe water sample after testing thereof.

When the water supply 225 in need of monitoring is incorporated in awater tank 240, as shown in FIG. 2, an active mixing module 280 can beincluded. Such an active mixing module 260 can comprise, but is notlimited to, a submersible mixing system that is usable for use instorage tanks (as shown in FIG. 2) and reservoirs (not shown).Optimally, active mixing module 260 will rapidly and completely mix thedisinfectant chemicals inserted via chemical feed nozzle 250 and/orammonia feed nozzle 255 into the entire volume of water supply 225 intank 230 or reservoir (not shown) or well (not shown), enabling rapidhomogenization and maximum water quality stability and reliability. Themethodologies and devices disclosed in U.S. Pat. Nos. 5,934,877,6,702,552, 7,488,151, 7,862,302, and 9,039,902, which are incorporatedby reference herein in their entireties, are suitable for use in somemixing aspects of the invention.

A number of embodiments have been described but a person of skillunderstands that still other embodiments are encompassed by thisdisclosure. It will be appreciated by those skilled in the art thatchanges could be made to the embodiments described above withoutdeparting from the broad inventive concepts thereof. It is understood,therefore, that this disclosure and the inventive concepts are notlimited to the particular embodiments disclosed, but are intended tocover modifications within the spirit and scope of the inventiveconcepts including as defined in the appended claims. Accordingly, theforegoing description of various embodiments does not necessarily implyexclusion. For example, “some” embodiments or “other” embodiments mayinclude all or part of “some”, “other,” “further,” and “certain”embodiments within the scope of this invention.

The invention claimed is:
 1. A method of determining a disinfectantcomposition of a municipal water supply from a water sample comprising:a. obtaining a water sample from a water source at a sampling location,wherein: i. the water sample is derived from a water treatment facility;ii. a chlorine-containing material and an ammonia containing materialare present in the water source; and iii. the sampling location islocated downstream from the water treatment facility; b. adding achlorine-containing material to the water sample in the presence of anoxidation reduction potential (ORP) measurement device; c. generating aplurality of ORP measurements during addition of the chlorine-containingmaterial to the water sample; d. estimating a concentration of one ormore of free ammonia, fully combined ammonia, monochloramine or amixture of dichloramine and trichloramine in the water sample, whereinthe estimation is derived from the relationship between the addedchlorine material and the plurality of ORP measurements; and e.determining a disinfectant composition of the water source at the watersampling location based upon the concentration calculation.
 2. Themethod of claim 1, wherein the concentration is estimated frommonitoring the rate of change of ORP measurement in millivolts as afunction of the amount of chlorine-containing material added to thewater sample.
 3. The method of claim 1, wherein the concentration isestimated by calculating a slope obtained by plotting the ORP of thewater sample versus the amount of chlorine-containing material added tothe water sample.
 4. The method of claim 1, wherein the disinfectantcomposition is determined as a real-time measurement.
 5. The method ofclaim 1, wherein the chlorine-containing material is added to the watersample in a known volume while generating the plurality of ORPmeasurements to determine the relationship between the added chlorinematerial and the plurality of ORP measurements.
 6. The method of claim1, further comprising comparing the plurality of ORP measurementsobtained from the water sample located downstream from the watertreatment facility to ORP measurements obtained from a water sampleobtained at the water treatment facility to determine disinfectionefficacy.
 7. The method of claim 1, wherein the estimated provides theconcentration of both free ammonia and monochloramine in the watersample.
 8. The method of claim 1, further comprising, after determiningthe disinfectant composition of the water source, adding additionalchlorine-containing materials and ammonia-containing materials to thewater source to achieve a desired level of the disinfectant composition.9. The method of claim 8, wherein an amount of the addedchlorine-containing materials and ammonia-containing materials isindependent of a concentration of the chlorine-containing materials andammonia-containing materials.
 10. The method of claim 1, wherein avolume of the water sample obtained from the water source is known. 11.A method of determining free ammonia composition of a water supplycomprising: a. obtaining a water sample from a water supply at asampling location; b. adding a chlorine-containing material to the watersample in the presence of an oxidation reduction potential (ORP)measurement device; c. generating a plurality of ORP measurements duringaddition of the chlorine-containing material to the water sample; and d.estimating a concentration of free ammonia in the water sample, whereinthe estimation is derived from the relationship between the addedchlorine material and the plurality of ORP measurements.
 12. The methodof claim 11, wherein a volume of the water sample obtained from thewater source is known.
 13. The method of claim 11, wherein the watersample is derived from a water treatment facility and the samplinglocation is located downstream from the water treatment facility. 14.The method of claim 11, further comprising maintaining a concentrationof free ammonia in the water supply within a range of greater than 0mg/L and less than about 0.1 mg/L.
 15. The method of claim 11, whereinthe method of determining free ammonia composition is substantially freeof a reagent other than chlorine and ammonia-containing materials. 16.The method of claim 11, wherein the concentration of free ammonia isestimated from monitoring the rate of change of ORP measurement inmillivolts as a function of the amount of chlorine-containing materialadded to the water sample.
 17. The method of claim 11, furthercomprising adding additional chlorine-containing materials when theestimated ammonia concentration is above a desired ammonia concentrationrange.
 18. A system for maintaining the disinfectant level of a potablewater supply comprising: a. a water quality assessment modulecomprising: i. a plurality of sensors comprising at least an oxidationreduction potential sensor; and ii. a control module in operationalengagement with the plurality of sensors; b. a water supply intended fordelivery of potable water to a consumer; c. a water sampling devicecomprising a fluid delivery means configured to provide a sample ofwater derived from the water supply to the water quality assessmentmodule; d. a chlorine feed source and an ammonia feed source, whereineach of the sources are independently: i. in operational engagement withthe water quality assessment module; and ii. in fluid communication withthe water supply, wherein the system is configured to measure and adjustthe chloramination level and the free ammonia levels of a potable watersupply prior to delivery of the water supply to the consumer.
 19. Thesystem of claim 18, wherein the water quality assessment module isconfigured to provide information regarding at least a disinfectantlevel of the water supply.
 20. The system of claim 18, wherein the watersupply is maintained in a water storage tank.
 21. The system of claim20, wherein the water storage tank includes a mixing module.
 22. Thesystem of claim 18, wherein the water sampling device further comprisesa pump.
 23. The system of claim 18, wherein the volume of the sample ofwater provided by the delivery means is known.
 24. The system of claim18, wherein the plurality of sensors further comprise a pH sensor and atemperature sensor.